<div class="btn-group" data-field="buttons" style="position: absolute; top: 50px; left: 35px;">
    <a class="btn btn-default" data-field="scale-minus"> - </a>
    <div class="btn-group" role="group">
        <button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" style="margin-right: 0px;">
            <span data-field="zoom">100%</span>
            <span class="caret"></span>
        </button>
        <ul class="dropdown-menu" style="min-width: 60px;">
            <li><a data-field="scale-to-300">300%</a></li>
            <li><a data-field="scale-to-150">150%</a></li>
            <li><a data-field="scale-to-100">100%</a></li>
            <li><a data-field="scale-to-50">50%</a></li>
        </ul>
    </div>
    <a class="btn btn-default" data-field="scale-plus"> + </a>
</div>